Although alkali halide crystals such as lithium iodide (LiI), sodium iodide (NaI), and cesium iodide (CsI), for example, can be activated with divalent rare-earth ions such as Eu(2+), such activated crystals have heretofore not been widely used as scintillators for radiation detection applications due to their incompatibility with the incorporation of divalent activator ions at relatively high levels—nominally between 0.5 and 5.0 weight percent (hereinafter expressed simply as %)—referred to herein as “heavily doped”. This is due to the fact that when divalent ions such as Eu2+ are added to the growing single crystals of monovalent-cation alkali halides at a level of between ˜0.5 and 5.0%, the resulting single crystals are effectively white and opaque due to the formation of so-called Suzuki Phase precipitates. These Suzuki-phase precipitates scatter the scintillator light thereby adversely affecting the light transmission and reducing the overall radiation detection performance (e.g. light yield and energy resolution) of the scintillator crystals—for either gamma-ray detection (or in the case of LiI:Eu2+ crystals containing preferably isotopically enriched 6Li as the neutron converter) for thermal neutron detection. Moreover, Suzuki-phase precipitates preclude the use of other divalent-doped alkali halide crystals for sundry optical applications.